Doctor blade mounting



- May 17, 1949. L. HORNBOSTEL DOCTOR BLADE MOUNTI NG Filed April 27, 1945 4 Sheets-Sheet 1 lLayo f/oelvaos c 0 W M 0 y 17, 1949- L. HORNBOSTEL DOCTOR BLADE MOUNTING 4 Sheets-Sheet 2.

Filed Apri1' 27, 1945 r2 VET 2 2271' 1.1.0 r0 Homveosrrg 12 4 VI 7 1 3 0 W m2 mm 4 Sheets-Sheet 4 L. HORNBOSTEL DOCTOR BLADE MOUNTING Hffys.

May 17, 1949.

Filed April 27, 1945 Patented May 17 1949 noc'ron BLADEMOUNTING Lloyd Hornbostel, Beloit, Wis., assignor to Belolt Iron Works, Beloit, Wis., a corporation. of Wisconsin Application April 27, 1945 Serial No. 590,709

Claims. 1

This invention relates to a doctor blade mounting, and more particularly to a doctor blade mounting for use in the making of paper or in the creping of paper or other web material.

It has heretofore been customary in the mounting of doctor blades to provide the doctor blade with end stub shafts which are journalled in bearings, and to secure weight arms to the stub shafts for holding the doctor blade against the roll, or cylinder, with the desired amount of pressure. It is difficult, if not impossible, with such prior .art doctor blade mountings to adjust the pres-- sure properly so as to cause the doctor blade to bear against the roll, or cylinder, with a uniform pressure throughout its length. Also,. in the case of relatively long doctor blades for tending a wide roll, or cylinder, difficulty has been experienced due to flexing of the doctor blade under the torsion exterted at its ends, with the result that the bearing pressure between the'doctor blade and the roll, or cylinder, varies at different points along the length of the doctor blade. In accordance with the present invention, uniform pressures between the doctor blade and the roll, or cylinder, are maintained throughout the length of the doctor blade by the use of fluid-oposcillating the doctor blade lengthwise of its axis.

erated diaphragms in conjunction with reducing valves and pressure gauges for insuring that exactly the same pressure and the desired amount of pressure is exterted in holding the doctor blade against the roll, or cylinder. For this purpose, the two or more controlling diaphragms are 'operated from a common source of fluid under pressure, such as compressed air, and indicat-- ing gauges are associated with each of the diaphragms to enable the operatorto control the pressures exerted by the fluid upon each of the diaphragms with great exactness.

Further, in the doctor blade mounting of my invention, the mounting itself is of rather massive construction while the doctor blade proper consists of a relatively thin, flexible metal blade. By virtue of the compartively massive mounting for the doctor blade, very little distortion due to the torque applied to the ends of the shaft take place. Consequently, since the diaphragms serve to equalize the torque imparted to the ends of the doctor blade shaft, a uniform pressure along the length of the doctor blade proper is maintained between the edge of the doctor blade and the roll, or cylinder, against which the blade is pressed.

In addition to providing for uniform pressure between'the doctor blade and roll, my doctor blade mounting construction includes means for of dirt, or'foreign material, at any one point between the doctor blade and the surface of the roll,

or cylinder, and thus to prevent scoring of the roll surface or tearing of the paper web at such point. The doctor blade mounting thus includes bearings for the ends of the doctor blade shaft to permit such oscillatory movement and also includes hangers for the shaft bearings that compensate for any slight misalignment of the shaft.

It is therefore an important object of this invention to provide a mounting for a doctor blade that is of such construction as to insure the maintenance of uniformly equal pressures the length of the doctor blade between the doctor blade and the roll, or cylinder, against which the doctor blade is pressed.

It is a further important object of this invention to provide a doctor blade mounting that includes means for controlling and maintaining a uniform pressure of the optimum amount between the doctor blade and the roll, or cylinder, against which the blade is pressed, and that also includes means for oscillating the doctor blade lengthwiseof its axis so as to reduce the tendency of the doctor blade to score the roll, or cylinder, or to tear the web of paper'that is being doctored from the surface of the roll, or cylinder.

It is a further important object of this invention to provide a doctor blade mounting that includes fluid pressure operated dlaphragms for effecting and maintaining a desired uniform pressure between the doctor blade proper and the roll, or cylinder, with which the blade cooperates in the removal of the web of paper from the roll, or in the creping and removal of the web, and that also includes manually operable means for independent operation of the doctor-blade mounting in the event of an emergency.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

On the drawings:

Figure 1 is a broken side elevational view of a paper machine roll, or cylinder, with which is associated a doctor blade mounting embodying the principles of my invention.

Figure 2 is a broken side elevational view, similar to Figure 1, but taken from the other side of the machine.

Figure 3 is a broken, enlarged front elevational view, with parts broken away and in section.

Figure 4 is a broken elevational view, partly in section, of the mechanism for oscillating the doctor blade mounting, the connection with which is shown broken away at the rlghthand lower end of Figure 3.

Figure 5 is a view, partly in section, taken substantially along the line V-V of Figure 3, illustrating one of the diaphragm mechanisms. a Figure 6 is a sectional view, with parts in elevation, taken substantially along the line VI--VI of Figure 5.

Figure '1 is a view partly in section and partly diagrammatic of the fluid pressure piping system to the diaphragms.

As shown on the drawings:

In Figures 1, 2 and 3, the reference numeral l indicates a roll, or cylinder, such as the drying cylinder of a paper machine or of a creping machine such as is used for the creping of paper. Said roll III is suitably mounted for revolution in accordance with any of the conventional arrangements for mounting and revolving such rolls. Longitudinally extending I-beams II and I2 form a part of any such usual or conventional frame ,as may be employed for the mounting of the roll l0. Said I-beams II and I2 extend longitudinally of the machine on either side of the roll In and are supported in part by upright frame members l3, of which there are a number on either side of the machine.

The doctor blade mounting of my invention is indicated generally by the reference numeral i4. As illustrated, the doctor blade mounting i4 is supported from the I-beams II and I2 by means of brackets l5 and i6 that are of sufficient length to enable the doctor blade mounting to be properly positioned with reference to the roll, or cylinder, l0. As shown, the doctor blade mounting I4 is positioned in front of and well below the horizontal axis of the cylinder I0, but other positions of the doctor blade mounting are contemplated.

The doctor blade mounting l4 includes a shaft l1 which is, in general, parallel to the axis of the roll Ill and the ends of which are lournalled in bearings indicated generally by the reference numerals i8 and ill. The bearings i8 and I9 are similarly mounted from the brackets I5 and I6, respectively, by means of plates and 2|. Since the two bearings l8 and 9 are identical, only the bearing I8 will be described.

Said bearing l8 comprises an open-ended cylindrical housing 22 on the top of which is formed an integral boss 23 that is internally threaded for receiving the lower end of a threaded hanger rod 24. Said hanger rod 24 extends freely through a guide ring 25 that may extend integrally from the plate 20 and that is formed with upper and lower segmental spherical surfaces 26 and 21 (Fig. 3). A collar nut 28 is threaded upon the hanger rod 24 below said guide ring 25 and is provided with a conformingly curved upper surface 29 for cooperation with the lower surface 21 of the guide ring. A second collar or nut 30 is threaded upon the upper end of the hanger rod 24 and is provided with a lower segmental spherical surface 3| for bearing against the upper guide ring surface 25. Each of said collars or nuts 28 and 30 is provided with wrench engageable holes 32 for turning the same to adjust the hanger rod 24 upwardly or downwardly. As will be apparent, the provision of the segmental spherical surfaces 26, 3| and 21, 29, together with the clearance between the hanger rod 24- and the guide ring 25, serves to permit slight movement of the hanger rod 24 from the vertical. The construction described thus comv pensates for any slight misalignment of the shaft H from its position parallel to the axis of the roll Ill.

The end of the shaft |1 that extends into the bearing housing 22 is reduced in diameter, as at 33, and is provided with a bearing sleeve 34 of such thickness as to compensate exactly for the reductionlin diameter of said shaft. Said bearing sleeve 34 comprises the inner bearing race of a ball bearing assembly that includes balls 35, an outer bearing sleeve or race 36 and end collars 31. A separate sleeve 38, of the same thickness as the inner bearing sleeve 34, forms a continuation thereof on the outer extended end 39 of said shaft II. The open ends of the housing 22 are closed by means of end seals 40 and 4| which are secured to said housing 22 by screws 42. The end seals 40 and 4| include suitable packing 43 for preventing loss of lubricant from the interior of said housing 22. The ball bearing assembly is retained within the housing 22 by means of split ring structure 44, between which and the housing 22 are provided segmental spherical surfaces 45 that render the split ring bearing block 44 selfmovement made possible by the adjustability of the hanger rods 24 in the ring guides 25. Said means, which are in general similar in construction to the vertically arranged bearing hangers just described, include a horizontally disposed hanger rod 46, one end of which is inserted into a bifurcated member 41, the ends of which are swivelly mounted upon a pin 52 carried by a plate 48 that is secured to the lower end of one of the brackets l5 or iii by means of bolts 49. Said hanger rod 46 extends freely through a ring guide 50 that is integrally formed with the bearing housing 22 and depends therefrom. On either side of the ring guide 50 is a nut or collar 5|,

' which is internally threaded to receive said hanger rod 46 and that is provided on the side toward the guide ring 50 with a segmental spherical surface for mating with a corresponding segmental spherical surface on said guide ring 50. The swivel mounting of an end of each of the hanger rods 46 about a pin 52 permits the shortening or lengthening of the vertical hanger mountings that include the hanger rods 24.

While the ends of the shaft |1 are journalled in the bearings l8 and I9, such bearings are intended merely to permit a limited turning movement of the shaft l1 suflicient to swing the doctor blade assembly, indicated generally by the reference numeral 53 toward and away from the surface of the roll Hi. This, limited turning movement of the shaft I1 is normally accomplished through the medium of fluid operated diaphragm mechanisms, but in the case of emergency may also be independently operated manually. The diaphragm mechanisms will now be described.

As illustrated in Figure 3, there are two such diaphragm mechanisms, indicated generally by the reference numerals 54 and 55, one for each of the ends of the shaft l1. Since the two diaphragm mechanisms are identical in construction and operation, only that cooperating with the extended end 39 of the shaft |1 will be described.

The diaphragm mechanism 54 is suspended from the under side of the I-beam II by means of a strap carrying at its lower end a pair of spaced plates 51 and 59 connected at their four corners by posts 69. As best shown in Figures and 6, the lower plate 59 is in the form of a ring thatv is provided with lugs 59a for receiving the posts or bolts 69. A circular diaphragm 6| is clamped between the underside of the ring 59 and a bottom closure plate 62, bolted to said ring 59 by means of bolts 62a. Said bottom closure plate 62 is downwardly dished to provide a fluid pressure chamber 63 beneath said diaphragm 6|. Piping 64 is connected to an opening 85 in said bottom closure plate 62 for the purpose of introducing a fluid under pressure into said chamber 63, as will later be described.

The free central portion of the diaphragm 6| is clamped between a circular lower plate 86 and a circular upper plate 61, the two plates being held together by means of bolts 68 that pass through the lower plate 66 and diaphragm 6i and are threaded into the upper plate 61. A strap 689 in the form of a closed loop encloses the diaphragm assembly and is supported from the diaphragm by a rectangularly shaped pad 69 that is secured to the upper surface of the upper plate 61 by means of bolts 19. The strap 689 is thus supported directly by the diaphragm 6| and is subject to the movements of said diaphragm in accordance with the amount of fluid pressure within the chamber 63.

The lower portion of said strap 689 is provided centrally with a cylindrical boss II into which is v below which are positioned nuts, or collars, 16 and ill, respectively, that are internally threaded for engagement with the threaded end 14. Said nuts, or collars, I6 and ll thus provide 'for vertical adjustment of the ring I5 along the hanger rod 12, while the clearance between the ring and the lower threaded end 14 permits of limited relative movement.

A pair of arms 18 extend outwardly and downwardly from the ring I5 to support at their lower ends a pair of cylindrical members 19 having aligned bores for receiving a pivot pin 89. A strap 8i has at its upper end an eye 82 (Fig. 1) that is pivotally mounted upon said pin 89 between the end members 19, 19. The lower end of said strap 8| is transversely bored to receive a pin 83 that extends through the spaced ears 86, 84 formed on a lever, indicated generally by the reference numeral 85. Said lever 85 is associated with a bell crank lever 86, which will now be described.

Said bell crank lever 96 is provided at one end with a cylindrical boss 81 that is keyed upon the extended end 39 of the shaft I1, as by means of a key 88. From said cylindrical hub portion 81 there extends an arm 89 that is bifurcated at its outer end to provide parallel spaced plates, 99, 99, which together constitute the other armof the bell crank lever 86. A handle 9| is secured to the outer of the bifurcated end plates 99 in the lower corner formed by the junction of the external edges of said plates. Said handle 9| serves for manual manipulation of the bell crank lever 86. Both of the plates 99 are provided inwardly of the lower corner aforesaid with cylindrical bosses 92, 92 (Figs. 1 and 3) through which extends a pin 93. The lever arm 85 previously referred to is formed with a cylindrical boss 94 that is bored to receive said pin 93. The pin 93 is removable when it is desired to move the doctor blade mounting manually. When, however, the doctor blade mounting is to be controlled or actuated through the medium of the diaphragms, the pin 93 is inserted in place'and left in place so longas the diaphragms continue to function.

At the extreme upper ends of the plates 99, 99, the plates are bored to receive stationary pins 95, 95, which extend inwardly in spaced relation for receiving spaced cylindricalbosses 96, 96 formed on the upper end of .the lever 85. Said bosses 96, 86 are integrally connected with another set of bosses 91, 91 that are at a lower level than the bosses 96 and that are bored to receive the pin 83 that passes through the lower end of the link 8|. The pin 83 thus serves as the fulcrum pivot pin for the lever when the removable pin 93 is removed. With the pin 93 removed, the pin 83 also serves as the pivot for the bell crank lever 86, so that by pulling forwardly on the handle 85a of lever 85 the operator can manually swing'the doctor blade assembly 53 away from the roll I9. This is accomplished by moving the pin about the pivot pin 83 as a center until the pin 95 is free to drop clear of the pin 83 (on the left hand side of the pin 83, as viewed in Fig. 1). The bell crank lever then swings downwardly and the doctor roll mounting swings away from the roll I9.

When however, the removable pin 93 is inserted in place to hold the lever arm 85 against movement, the link 8| and bell crank lever 86 function as a rigid unit and are subject to the action of the diaphragm in controlling the position of the doctor blade assembly 53 relative to the surface of the roll I9.

The doctor blade assembly 53 includes a pair of end sleeves I99, I99 that are adapted to be secured upon the shaft IT for turningmovement therewith. A doctor blade supporting member Illl is mounted upon said shaft I'I between said end sleeves I99, I99, to which said supporting member may be rigidly secured, or with which the supporting member may be integrally formed. The supporting member I9I comprises a massive bar of metal of generally rectangular cross section. An upstanding rib I92, which may be formed integrally with the body of the blade supporting member IN, is slotted along its upper edge to receive the doctor blade proper, indicated by the reference numeral I93. Said doctor blade proper I93 may be formed of relatively thin metal and is provided with an accurately ground working edge I94 adapted to bear against the surface of the roll I9 when in operation.

The mechanism for oscillating the doctor blade 53 will now be described. Said mechanism, as best shown in Figures 2 and 4, includes a motor I95 supported by a strap I96 from I-beams II and I2. The driving shaft I91 of said motor is connected to a coupling I98 with a driven shaft I99. Said driven shaft I99 is journalled at its free end in a bearing I I9 also supported by a strap III from the I-beams II and I2. The driven shaft I99 carries an eccentric II2 upon which is mounted an eccentric strap I I3. A crank arm I I4 is secured to said eccentric strap I I3 by means of a bifurcated end member H5. The ends of said bifurcated member II 5 are secured to said eccentric. strap 3 by means'of pivot pins H6, II6, and said bifurcated end member is secured to one end of the crank arm H4 by means of a nu, Ill. The other end of said crank arm H4 is threaded, as at II8 for attachment to a' having a segmental spherical inner wall I22 for receiving the ball end I23 of a rod I24. Said rod I24 may be integrally formed with or otherwise secured to the adjacent end I25 (Fig. 3) of the shaft II. As will be obvious, when the motor I is driven, an oscillatory movement will be imparted to the shaft I! through the eccentric and connections just described.

' The operation of the diaphragm mechanisms will now be explained in conjunction with the diagrammatic showing in Figure '7. A fluid under pressure, such as compressed air, is connected to a main pipe I30, which has mounted in it athree-way valve I3I. Said three-way valve I3I' has one connection to an exhaust pipe I32 and another connection to a continuation of the pipe I30, indicated by the reference numeral I 30a. By turning a handle I33 on said three-way valve I3I, communication can be established through the valve between the pipes I30 and I30a, or between the pipe I30a and the exhaust pipe I32. The pipe I30a is connected by means of branch piping I34 to pipe lines I35 and I35a, in which are positioned check valves I36 and I36a, and also to pipe lines I31 and I3Ia, in which are positioned reducing valves I38 and I38a. Said pipe lines I35 and I31 are connected to a common pipe line I30 provided with a T I40. The pipe 34 leading from the pressure fluid chamber 63 within the diaphragm mechanism is connected to one branch of said T I40 and a pressure indicating gauge I M is connected to the other branch of said T I40. Similarly, the pipe lines I35a and I3'Ia are connected to a common pipe I39a, which is connected through a T I40a with the pipe 64a communicating with the pressure fluid chamber 63a of the diaphragm mechanism. A pressure gauge I4Ia is similarly connected to the T I40a.

With the doctor blade mounting assembled as illustrated in the drawings, the amount of pressure between the doctor blade edge I04 and the surface of the roll H0 is controlled through the diaphragm mechanisms by adjusting the pressure by means of the reducing valves I36 and I30a to the amount of pressure desired, as indicated on the pressure indicators MI and Mia. The pressure can thus be regulated until it is exactly the same at both ends of the shaft IT. This pressure, as is obvious, is translated into a torque applied to the shaft I1 and from the shaft II through the sleeves I00, I00 and the associated blade mounting member I M to the blade proper I03. As the fluid pressure within the diaphragm fluid pressure chambers 63 and 63a is increased, the

diaphragms 6| are distended upwardly to elevate the straps 680 and through the hanger rods I2 and associated elements to elevate the pivot pins 83, and thus raise the free ends of the bell crank levers 86. Since the bell crank levers 83 are keyed through the hubs 8! to the ends 39 of the shaft I1, said shaft I! has applied to it a torque tending to rotate the shaft in such a Way as to move the doctor blade I03 toward the surface of the roll I0, or if already in contact with such surface to cause said doctor blade I 03 to press more firmly against said roll surface.

During operation, the oscillating mechanism is set into movement by energizing the motor I05, causing the doctor blade I03 to oscillate in the direction of its length while being pressed against the surface of the roll I0. The amplitude of such oscillation is, of course, relatively slight, but should be sufficient to prevent scoring of the surface of the roll I0 and also prevent the accu- 8 mulation of dirt or foreign matter at any point between the doctor blade edge I04 and the roll surface.

In order to release the torque impressed upon the shaft I! and doctor blade assembly 53 through the diaphragm mechanisms, it is only necessary to move the three-valve I3I to establish communication between the pipe line I30a and the exhaust pipe I32. With this setting of the valve, pressure is relieved from the fluid pressure chambers 63 and 03a through the check valves I36 and I3Ba and out through the exhaust pipe I32.

In addition to this means of relieving fluid pressure and thus rendering the diaphragm mechanisms inoperative, the operator may remove the pins 93 and manually operate the bell crank levers by means of their handles 05a, using the handle 9| as an aid in this manual operation. By moving the handles 85a forwardly, the bell crank levers 86 may be swung slightly about the pivot pin 83 and to the back side thereof to permit the pivot pins 83 and associated parts to drop down. The shaft I1 is thereby rotated sufficiently to swing the doctor blade assembly 53 away from the surface of the roll I0.

The adjusting mechanisms already described, such as those for permitting horizontal and vertical adjustment of the shaft bearings I8 and I9, make possible a very nice adjustment of the doctor blade I03 relative to the surface of the roll I0 as well as a very delicate control of the pressures that are maintained between the doctor blade edge I04 and the roll surface.

In place of diaphragms, fiuid pressure operated pistons may be employed.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the ap-- fluid pressure actuated mechanisms and said shaft for rotating said shaft.

2. A doctor blade mounting comprising a rotatable shaft, a doctor blade assembly fixedly secured to said shaft, and including a doctor blade rotatable with said shaft into and out of pressure contact with a roll, fluid pressure actuated mechanisms, hangers operatively connected to said mechanisms, first levers secured to said shaft, second levers pivotally connected to said first levers, and removable means locking said first and second levers together to provide a rigid unitary connection between said mechanisms and said shaft, whereby said fluid pressure'actuated mechanisms can be operated to hold said doctor in pressure contact with the roll, said second levers being manually operable upon removal of said locking means to effect relative movement be tween said hangers and said first levers and cause said shaft to rotate said doctor blade out of pressure engagement with the roll.

3. A doctor blade mounting comprising a shaft, bearings for the ends of said shaft, a doctor blade assembly fixedly secured to said shaft, a doctor blade forming a part of said assembly, means adjustably supporting said bearings to align said shaft with respect to a roll to be doctored, fluid, pressure actuated mechanisms, hangers of adjustable length depending from said mechanisms, first levers fixedly secured to said shaft to rotate the same, second levers pivotally connected to said first levers, of adjustable effective length straps pivotally connected said second levers to said hangers, and removable means locking said first and second levers to provide a rigid unitary connection between said mechanisms and said shaft to hold said doctor blade in pressure contact with the roll, said second levers being operable upon removal of said locking means to increase the effective lengths of said straps to cause rotation of said shaft and movement of said doctor blade away from said roll.

4. A doctor blade mounting comprising a shaft, a doctor blade assembly fixedly secured to said shaft, bearings for' rotatably supporting said shaft, fluid pressure actuated mechanisms, a strap connected to each of said mechanisms, a cylindrical boss on the lower portion of said strap, a hanger rod having threaded ends locked at its upper end to said boss, 9. ring threaded onto the lower end of said hanger and vertically threadably adjustable thereon, a pair of arms extend- 111g outwardly and downwardly from said ring, a pair of cylindrical members having aligned bores at the lower ends of said arms, a second strap pivotally carried by said cylindrical members, a first lever pivotally connected to said secand strap, a second lever pivotally connected to said first lever and to said shaft, and a member locking said first and second levers to form a unitary operative connection between said fluid pressure actuated mechanisms and said shaft for rotating said shaft, the position of said doctor blade being adjustable by adjusting said ring vertically thereby rotating said shaft.

5. In the combination of a doctor blade mounting with a roll against which the doctor blade is to be pressed, a shaft, bearings for supporting said shaft for rotation, a doctor blade assembly nnrnanncns crrnn The following references are of record in the file of this patent:

UNITED STATESPATEN-TS Number Name Date 398,714 Farr Feb. 26, 1889 1,150,423 Dunbar Aug. 17, 1915 1,644,917 Frossard et a1 Oct. 11, 1927 1,699,641 vasel Jan. 22, 1929 1,972,346 Juline Sept. 4, 1934 2,830,889

Holcomb Oct. 5, 1948 

